Clear QAM refers to a broadcast service using an unencrypted cable channel. When Clear QAM is used, a user of a DTV having a digital cable broadcast program reception chip mounted therein as well as a subscriber of an existing cable broadcast service can view the broadcasting program of an unencrypted channel. When Clear QAM is introduced, as distribution channels of high-quality content are diversified, content may be diversified. In addition, a high-quality ultra high definition (UHD) broadcast service based on a wide bandwidth is possible.
However, video services having a variety of resolutions are not all supported by Clear QAM. Accordingly, there is a need for technology related to Clear QAM capable of supporting the video services having a variety of resolutions.